Gray Bichir

Diagnosis: Polypterus senegalus is characterized by jaws of equal length or an upper jaw slightly longer than lower jaw and a pectoral fin not reaching the first dorsal ray (Ref. 2756, 2835, 42908, 43035, 81263).Description: Polypterus senegalus senegalus has a cylindrical or faintly depressed body; its height comprised 7,1 to 10,6 times in body length and head length 5 to 7 times in body length (Ref. 2835, 42908, 81263). Head not flattened, 1,6 to 2 times longer than broad; snout acuminate and upper jaw faintly prominent or jaws of equal length; interorbital region convex; eye diameter comprised 5 to 8 times in head length (Ref. 1989, 2756, 2835, 81263). Dorsal fin with 8-11 rays, anteriorly separated from each other when folded, followed by 16-18 dorsal and caudal articulated rays; anal fin with 14-17 rays; pectoral fin rounded, not getting the level of the first dorsal ray (Ref. 2835, 42908, 81263). Ganoid scales (Ref. 42904): 53-61 in lateral line, 34-40 around body in front of dorsal fin and 14-21 predorsal scales; lateral line scales simply perforated, not grooved, without posterior notched border (Ref. 2835, 42908, 81263). Polypterus senegalus meridionalis has a cylindrical or subcylindrical body; its height comprised 7 to 9 times in body length and head length 4,5 to 6,8 times in body length (Ref. 43035). Head not flattened, 1,5 to 1,75 times longer than broad; snout acuminate and upper jaw faintly prominent or jaws of equal length; eye diameter comprised 4,25 to 8 times in head length (Ref. 43035). Dorsal fin with 9-10 rays, anteriorly separated from each other when folded; anal fin with 14-17 rays; pectoral fin not getting the level of the first dorsal ray (Ref. 42908, 43035). Ganoid scales (Ref. 42904): 55-58 in lateral line, 34-36 around body in front of dorsal fin and 15-20 predorsal scales; lateral line scales perforated, not grooved, without posterior notched border (Ref. 42908, 43035).Colouration: In alcohol, Polypterus senegalus senegalus with upper part of body uniformly grey or olive-coloured, belly whitish; young specimens with three longitudinal dark stripes on the flanks, which disappear at an early age; fins grey-coloured (Ref. 367, 2835, 81263). Polypterus senegalus meridionalis with upper part of body uniformly olive-grey coloured; juveniles with three longitudinal black stripes on the flanks (Ref. 43035, 44841).

Macrogyrodactylus Infestation 2. Parasitic infestations (protozoa, worms, etc.)

In Polypterus senegalus courtship starts with a series of leaps from the surface by usually only one of the pair at a time, followed by a slow descent through the water; after a while the male stays very close to the female and at times the female will remain motionless in the water and the male will come up to her from behind and nudge her with sidewise movements of his head; the enlarged and swollen anal fin of the male is folded in a cup-like fashion and is used to brush the female (Ref. 42791). No nest is constructed, but the eggs are laid a few at a time throughout the thick vegetation (Ref. 42791). The larvae, which move about with the male parent in a dense school, are provided with accessory gills and appear very salamander-like (Ref. 42791).

Potamodromous. Migrating within streams, migratory in rivers, e.g. Saliminus, Moxostoma, Labeo. Migrations should be cyclical and predictable and cover more than 100 km.

Dorsal spines (total): 811; Analspines: 1417; Vertebrae: 53 - 59

It inhabits marginal swamps and freshwater lagoons (Ref. 3066). It feeds on insects, crustaceans, molluscs, fish and frogs; plant fragments and seeds are also ingested (Ref. 28714). But Polypterus senegalus senegalus is mainly insectivorous (Ref. 367). Also Ref. 52840.

This species inhabits marginal swamps and freshwater lagoons (Ref. 3066) and it appears to favor sheltered inshore habitats (Ref. 3034); it inhabits the muddy regions at the sides of rivers and swampy waters, where it lies quiet or glides about with snake-like movements (Ref. 49805). During the hottest hours of the day, it comes to the surface just on the outer edge of the vegetation, and it goes back to the bottom when disturbed (Ref. 45962). It feeds on insects, crustaceans, mollusks, frogs and fishes (Ref. 4903, Ref. 28714). Polypterus senegalus senegalus is mainly insectivorous (Ref. 367). Longevity of Polypterus senegalus in captivity can be 34 years and more (Ref. 48954).Larval fish 1.1-3.8 cm SL were found in papyrus root mat and juveniles up to 10 cm SL retaining external gills were found in fringing water hyacinth. Feeds mainly on fishes (Ref. 9695), insects, crustaceans, mollusks, frogs as well as on plant fragments and seeds.

fisheries: commercial